Impact of annealing temperature and ferrite content embedded in SiO2 matrix on the structure, morphology and magnetic characteristics of (Co0.4Mn0.6Fe2O4)δ (SiO2)100-δ nanocomposites

Abstract In this work, the (Co0.4Mn0.6Fe2O4)δ (SiO2)100-δ (δ = 0–100%) nanocomposites were synthesized via a modified sol-gel method followed by annealing at 200, 400, 700 and 1100 °C. The main purpose of this paper is to find a relationship between the nanoparticle structure and morphology and the magnetic parameters at different annealing temperatures and different ferrite contents embedded in the SiO2 matrix. The powder X-ray diffraction (XRD) and Fourier transform infrared (FT-IR) spectroscopy were used to investigate the structural properties, such as crystalline phases, degree of crystallinity, crystallite size and the formation of chemical bonds, while transmission electron microscopy (TEM) was used to examine the morphological features of nanocomposites. The dependence of saturation and remanent magnetizations, coercivity and magnetic anisotropy on ferrite content embedded in SiO2 matrix were investigated by vibrating sample magnetometry (VSM). The XRD data showed that the crystallite size increase with increasing annealing temperature and amount of ferrite content embedded in the SiO2 matrix. The SiO2 matrix exhibits diamagnetic behavior with a small ferromagnetic fraction, Co0.4Mn0.6Fe2O4 embedded in SiO2 matrix presents superparamagnetic-like behavior, while unembedded Co0.4Mn0.6Fe2O4 a high-quality ferromagnetic type behavior.